Molten metal pouring device and centrifugal casting machine using the same

ABSTRACT

A molten metal pouring device is configured to pour molten metal into a mold cavity formed between an upper mold and a lower mold of a centrifugal casting machine. The molten metal pouring device includes a pouring unit including an end formed with a pouring hole, through which the molten metal is poured into the mold cavity, the end of the pouring unit being inserted into a riser formed along a rotation axis of the upper mold and being drawn out of the riser as the molten metal is poured, a stopper inserted into the pouring unit to open and close the pouring hole so as to adjust the flow of the molten metal, and a base unit, to which the pouring unit is mounted, the base unit being configured to lift the pouring unit up and down.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims under 35 U.S.C. §119(a) the benefit of Korean Patent Application No. 10-2015-0130527, filed Sep. 15, 2015 in the Korean Intellectual Property Office, the entire contents of which are incorporated by reference herein.

BACKGROUND

1. Field of the Invention

The present invention relates to a molten metal pouring device and a centrifugal casting machine using the same, and more particularly to a molten metal pouring device capable of preventing turbulence while molten metal is being poured.

2. Description of the Related Art

In general, aluminum casting methods are classified into a high pressure die casting method, characterized by low product quality and high productivity, and a low pressure/gravity die casting method, characterized by high product quality and low productivity.

In the case of a typical horizontal-type centrifugal casting method, a mold can be filled with molten metal using centrifugal force. However, because the duration for which molten metal is poured and the speed with which the molten metal is poured cannot be precisely controlled, the molten metal becomes turbulent while it is being poured. Such turbulence may cause problems in that the mold is nonuniformly filled with molten metal, gas bubbles are introduced into the mold, and the hardness of the casting is decreased. Therefore, the use of the centrifugal casting method is limited to pipes and the like, which have a relatively simple shape.

In order to remedy the shortcomings of the horizontal-type centrifugal casting method, vertical-type centrifugal casting methods have been developed, one of which is disclosed in Korean Patent Publication No. 10-2011-0048631. According to Korean Patent Publication No. 10-2011-0048631, balance weights are radially mounted to a turntable, and an asymmetric mold is maintained in a balanced state during rotation by adjusting angles of inclination of the balance weights, the number of balls to be inserted into the balance weights, and the positions of the balls in the balance weights.

However, the centrifugal casting machine of Korean Patent Publication No. 10-2011-0048631 does not have a structure for preventing turbulence while molten metal is being poured, and thus still has a problem in that the material properties of regions deep in the mold differ from those near the molten metal pouring hole.

As shown in FIG. 1A (RELATED ART), if the density with which the mold is filled with the molten metal is decreased due to turbulence that occurs near the molten metal pouring hole, hardness is also decreased.

SUMMARY

Therefore, it is an object of the present invention to provide a molten metal pouring device and a centrifugal casting machine using the same, in which a pouring unit is lifted up and down to adjust whether molten metal is poured and an extent to which the molten metal is poured, thereby preventing turbulence while the molten metal is being poured and manufacturing casting products having uniform material properties.

In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a molten metal pouring device for pouring molten metal into a mold cavity formed between an upper mold and a lower mold of a centrifugal casting machine, which are configured to be rotated while in an engaged state, the molten metal pouring device including a pouring unit including an end formed with a pouring hole, through which the molten metal is poured into the mold cavity, the end of the pouring unit being inserted into a riser formed along a rotation axis of the upper mold and being drawn out of the riser as the molten metal is poured, a stopper inserted into the pouring unit through the other end of the pouring unit and configured to open and close the pouring hole, so as to adjust flow of the molten metal, and a base unit, to which the pouring unit is mounted, the base unit being configured to lift the pouring unit up and down.

The pouring unit may include a lower member configured to be inserted into the upper mold and formed to have a pipe shape having an outer diameter of a size corresponding to an inner diameter of the riser, and an upper member extending from the lower member in a funnel shape, and the stopper may be formed to have a column shape having a diameter that is less than an inner diameter of the lower member and greater than a diameter of the pouring hole.

The stopper may be pointed at an end thereof, so as to be inserted into the pouring hole.

The molten metal pouring device may further include a servo-motor mounted to the base unit, and a seesaw member connecting the servo-motor and the stopper.

In accordance with another aspect of the present invention, there is provided a centrifugal casting machine having an upper mold and a lower mold configured to be rotated while in an engaged state and defining a mold cavity therebetween to receive molten metal poured thereinto, the centrifugal casting machine including a molten metal pouring device configured to be lifted up and down so as to be inserted into or drawn out of a riser formed along a rotation axis of the upper mold, thereby adjusting whether the molten metal is poured and a speed with which the molten metal is poured, a driving module configured to rotate a rotating shaft having an end coupled to the lower mold, a cooling unit configured to cool the upper mold and the lower mold using cool air, and an electric heater unit configured to heat the upper mold and the lower mold.

The cooling unit may include an upper cooler including a first chamber coupled to a top of the upper mold and a first pump for supplying cool air to the first chamber through a first passage, and a lower cooler including a second chamber coupled to a bottom of the lower mold and communicating with a second passage formed in the rotating shaft and a second pump for supplying cool air to the second chamber through the second passage.

The electric heater unit may include an upper heater including a first heating wire mounted to a top of the upper mold and a first socket connected with the first heating wire and mounted to a bottom surface of an upper flange extending from a periphery of the upper mold, a lower heater including a second heating wire mounted to a bottom of the lower mold and a second socket which is connected with the second heating wire, mounted to a top surface of a lower flange extending from a periphery of the lower mold, and engaged with the first socket, a rotary connector connected with the second socket and mounted to the other end of the rotating shaft, and a power supply connected with the rotary connector to supply electricity to the same.

The driving module may include a motor, a driving belt for transmitting rotational force from the motor to the rotating shaft, and a brake configured to selectively contact the driving belt to stop rotation of the rotating shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1A (RELATED ART) is a view showing the results of measuring the hardness of respective portions of a casting manufactured using a conventional centrifugal casting machine, and FIG. 1B is a view showing the results of measuring the hardness of respective portions of a casting manufactured using a centrifugal casting machine according to an embodiment of the present invention;

FIG. 2 is a front sectional view illustrating the overall appearance of a centrifugal casting machine according to an embodiment of the present invention;

FIG. 3 is a side sectional view illustrating a pouring unit of a centrifugal casting machine according to an embodiment of the present invention; and

FIG. 4 is a view illustrating a driving module and a power supply according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g. fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Throughout the specification, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. In addition, the terms “unit”, “-er”, “-or”, and “module” described in the specification mean units for processing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

Further, the control logic of the present invention may be embodied as non-transitory computer readable media on a computer readable medium containing executable program instructions executed by a processor, controller or the like. Examples of computer readable media include, but are not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards and optical data storage devices. The computer readable medium can also be distributed in network coupled computer systems so that the computer readable media is stored and executed in a distributed fashion, e.g., by a telematics server or a Controller Area Network (CAN).

Unless otherwise defined, all terms used in disclosing embodiments of the invention, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

As shown in FIGS. 2 and 3, a molten metal pouring device according to an embodiment of the present invention is configured to pour molten metal M into a mold cavity C, which is formed between an upper mold 11 and a lower mold 12 of a centrifugal casting machine, which are configured to be rotated while in an engaged state. The molten metal pouring device includes a pouring unit 110, a stopper 120, and a base unit 140.

The pouring unit 110 includes a lower member 111, which is formed to have a pipe shape to permit the molten metal to flow therethrough and has a uniform diameter, and an upper member 112, whose diameter gradually increases toward the upper end thereof. That is, the pouring unit 110 has a funnel shape due to the narrow pipe-shaped lower member 112 and the wide circular upper member 112, into which the molten metal M is introduced. A pouring hole 113 is formed in the bottom of the lower member 111. The diameter of the pouring hole 113 is smaller than that of the lower member 111.

The bottom portion of the pouring unit 110, in which the pouring hole 113 is formed, is inserted into a riser 13 that is formed along the central axis of the upper mold 11. The riser functions to smoothly feed molten metal to the casting, which generally shrinks as it solidifies, apply a predetermined pressure to the casting, and reduce a temperature gradient, thereby helping produce castings without shrinkage defects. The riser 13 formed at the upper mold 11 is an open-top riser, which is formed vertically and communicates with the outside.

The stopper 120 has a column shape, which is inserted through the upper member 112 so as to open and close the pouring hole 113. The stopper 120 is formed to be thinner than the diameter of the lower member 111 so as to be able to be inserted into the lower member 111, but is formed to be thicker than the diameter of the pouring hole 113 so as to seal the pouring hole 113 when it comes into contact with the pouring hole 113. The stopper 120 is pointed at the lower end thereof so as to be partially inserted into the pouring hole 113, thereby securing an excellent sealing effect. Further, the stopper 120 has an effect of preventing turbulence by assisting the smooth pouring of the molten metal when the molten metal is initially poured as the stopper 120 ascends.

The base unit 140 functions not only to support the stopper 120 and the pouring unit 110 but also to lift them up and down. That is, the base unit 140 lifts the pouring unit 110 up and down so that the lower member 111 can be inserted into or drawn out of the riser 13. Through the structure whereby the pouring unit 110 is lifted up and down, it becomes possible to adjust an extent to which the molten metal is poured into the mold. The base unit 140 includes a base plate 141, on which the stopper 120 and the pouring unit 110 are mounted, and a lift 142 for lifting the base plate 141 up and down.

The reason for lifting the pouring unit 110 up and down using the base unit 140 is as follows: when the molten metal is initially poured, the pouring unit 110 is inserted into the riser 13 to minimize the distance that the molten metal falls, thereby preventing turbulence, and when the molten metal has been poured to a certain extent, the pouring unit 110 is drawn out of the riser 13, thereby further smoothening the supply of the molten metal.

The base plate 141 is mounted with a servo-motor 131 configured to generate a piston motion and a seesaw member 132 for connecting the servo-motor 131 and the stopper 120. When the driving unit of the servo-motor 131 ascends, one end of the seesaw member 132, which is coupled to the servo-motor 131, also ascends. At the same time, the other end of the seesaw member 132, which is coupled to the stopper 120, descends, and thus the stopper 120 also descends. The seesaw member 132 is provided with a hinge shaft in the middle, about which the seesaw member 132 pivots. Since the servo-motor 131 can be precisely controlled, the speed with which the molten metal is poured can be precisely adjusted by controlling the degree to which the stopper 120 is separated from the pouring hole 113.

The servo-motor 131 is hinged to the base plate 141 so as to pivot with respect to the base plate 141, thereby preventing interference between the seesaw member 132 and the servo-motor 131 while the seesaw member 132 pivots.

As shown in FIGS. 2, 3 and 4, the centrifugal casting machine includes the above-described molten metal pouring device, a driving module 400 configured to rotate a rotating shaft 20 connected with the lower mold 12, a cooling unit 200 configured to cool the upper and lower molds using cool air, and an electric heater unit 300 configured to heat the upper and lower molds.

The molten metal pouring device is structured such that the pouring unit can be lifted up and down so as to be inserted into or drawn out of the riser 13 formed along the rotation axis of the upper mold 11, thereby adjusting whether the molten metal is poured and the speed with which the molten metal is poured. Since the detailed explanation of the constitution and function of the molten metal pouring device has been made above, any further explanation will be omitted.

The rotating shaft 20 is coupled to the center portion of the lower mold 12 so as to be rotated therewith, and the upper mold 11 is engaged with the lower mold 12 so as to be rotated therewith. That is, although the rotating shaft 20 is not in direct contact with the upper mold 11, the rotating shaft 20 is connected with the upper mold 11 through the lower mold 12.

The driving module 400 includes a motor 410 for supplying rotational force, a driving belt 420 for transmitting the rotational force from the motor 410 to the rotating shaft 20, and a brake 430 for stopping the movement of the driving belt 420. The brake 430 is disposed apart from the driving belt 420 by a predetermined distance. The brake 430 is movably mounted, and comes into contact with the driving belt 420 to stop the same as needed.

The cooling unit 200 includes an upper cooler 210, which includes a first chamber 213 coupled to the top of the upper mold 11 and a first pump 211 for supplying cool air to the first chamber 213 through a first passage 212, and a lower cooler 220, which includes a second chamber 223 coupled to the bottom of the lower mold 12 and communicating with a second passage 222 formed in the rotating shaft 20 and a second pump 221 for supplying cool air to the second chamber 223 through the second passage 222.

The first chamber 213 has a hole formed in the center portion thereof, through which the pouring unit 110 is inserted. The portion of the first chamber 213 around the pouring unit 110 defines a space through which cool air flows. One end of the first passage 212 is coupled to the center portion of the top of the first chamber 213, through which cool air is introduced into the first chamber 213. The first chamber 213 has an outlet port formed at the periphery thereof, through which cool air is discharged outside from the first chamber 213. That is, the cool air flowing from the center portion of the first chamber 213 to the periphery of the first chamber 213 functions to cool the top surface of the upper mold 11.

Similarly, the bottom of the second chamber 223 is connected with the second passage 222, through which cool air is supplied into the second chamber 223. The cool air supplied into the second chamber 223 cools the lower mold 12, and is discharged outside from the second chamber 223 in the radial direction.

The electric heater unit 300 includes an upper heater 330 for heating the upper mold 11, a lower heater 340 for heating the lower mold 12, a power supply 310 for supplying electricity to the upper heater 330 and the lower heater 340, and a rotary connector 320 coupled to a lower end portion of the rotating shaft 20 so as to connect the power supply 310 and the lower heater 340.

The upper heater 330 includes a first heating wire 331 mounted to the top of the upper mold 11 and a first socket 332 for supplying electricity to the first heating wire 331, thereby heating the upper mold 11. The lower heater 340 includes a second heating wire 341 mounted to the bottom of the lower mold 12 and a second socket 342 for supplying electricity to the second heating wire 341, thereby heating the lower mold 12. The second socket 342 is engaged with the first socket 332 so as to be rotated therewith.

Because of the use of the rotary connector 320, electricity can be continuously supplied even if the rotating shaft 20 is rotated. Further, the first socket 332 and the second socket 342, which are mounted to an upper flange 14 and a lower flange 15, which extend outwards from the upper mold 11 and the lower mold 12, can be rotated while in an engaged state, thereby also ensuring the continuous supply of electricity to the first heating wire 331.

The driving module 400 includes a motor 410, a driving belt 420 for connecting the motor 410 and the rotating shaft 20 so that they rotate together, and a brake 430 configured to selectively contact the driving belt 420 to stop the rotation of the rotating shaft 20.

When the upper mold 11 and the lower mold 12 are separated from each other, it is necessary to minutely adjust the position of the lower mold 12 by rotating the rotating shaft 20 so that the first socket 332 and the second socket 342 are located at the positions corresponding to each other. At this time, it may be difficult to achieve minute adjustment using only the motor 410. Therefore, when the lower mold 12 is located at a desired position, the brake 430 is operated to stop the driving belt 420, thereby eventually stopping the rotation of the rotating shaft 20. Accordingly, electricity can be smoothly supplied to the first heating wire 331 to heat the upper mold 11.

As is apparent from the above description, the molten metal pouring device and the centrifugal casting machine using the same according to the present invention have the following effects.

First, the mold can be evenly filled with molten metal by preventing turbulence while the molten metal is being poured.

Second, the molten metal pouring speed and pouring duration can be freely adjusted.

Finally, the process of heating and cooling the mold can be freely performed even while the mold is rotated.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

What is claimed is:
 1. A molten metal pouring device for pouring molten metal into a mold cavity formed between an upper mold and a lower mold of a centrifugal casting machine, which are configured to be rotated while in an engaged state, the molten metal pouring device comprising: a pouring unit including an end formed with a pouring hole, through which the molten metal is poured into the mold cavity, the end of the pouring unit being inserted into a riser formed along a rotation axis of the upper mold and being drawn out of the riser as the molten metal is poured; a stopper inserted into the pouring unit through the other end of the pouring unit and configured to open and close the pouring hole, so as to adjust flow of the molten metal; and a base unit, to which the pouring unit is mounted, the base unit being configured to lift the pouring unit up and down.
 2. The molten metal pouring device according to claim 1, wherein the pouring unit includes a lower member configured to be inserted into the upper mold and formed to have a pipe shape having an outer diameter of a size corresponding to an inner diameter of the riser, and an upper member extending from the lower member in a funnel shape, and the stopper is formed to have a column shape having a diameter that is less than an inner diameter of the lower member and greater than a diameter of the pouring hole.
 3. The molten metal pouring device according to claim 2, wherein the stopper is pointed at an end thereof, so as to be inserted into the pouring hole.
 4. The molten metal pouring device according to claim 1, further comprising: a servo-motor mounted to the base unit; and a seesaw member connecting the servo-motor and the stopper.
 5. A centrifugal casting machine having an upper mold and a lower mold configured to be rotated while in an engaged state and defining a mold cavity therebetween to receive molten metal poured thereinto, the centrifugal casting machine comprising: a molten metal pouring device configured to be lifted up and down so as to be inserted into or drawn out of a riser formed along a rotation axis of the upper mold, thereby adjusting whether the molten metal is poured and a speed with which the molten metal is poured; a driving module configured to rotate a rotating shaft having an end coupled to the lower mold; a cooling unit configured to cool the upper mold and the lower mold using cool air; and an electric heater unit configured to heat the upper mold and the lower mold.
 6. The centrifugal casting machine according to claim 5, wherein the cooling unit includes: an upper cooler including a first chamber coupled to a top of the upper mold and a first pump for supplying cool air to the first chamber through a first passage; and a lower cooler including a second chamber coupled to a bottom of the lower mold and communicating with a second passage formed in the rotating shaft and a second pump for supplying cool air to the second chamber through the second passage.
 7. The centrifugal casting machine according to claim 5, wherein the electric heater unit includes: an upper heater including a first heating wire mounted to a top of the upper mold and a first socket connected with the first heating wire and mounted to a bottom surface of an upper flange extending from a periphery of the upper mold; a lower heater including a second heating wire mounted to a bottom of the lower mold and a second socket which is connected with the second heating wire, mounted to a top surface of a lower flange extending from a periphery of the lower mold, and engaged with the first socket; a rotary connector connected with the second socket and mounted to the other end of the rotating shaft; and a power supply connected with the rotary connector to supply electricity to the same.
 8. The centrifugal casting machine according to claim 5, wherein the driving module includes: a motor; a driving belt for transmitting rotational force from the motor to the rotating shaft; and a brake configured to selectively contact the driving belt to stop rotation of the rotating shaft. 